Tow dewatering jet device

ABSTRACT

In a process for treating continuous length filamentary tow of man-made fiber that is moved through a heated water bath, drafted and then in due course of processing is subsequently moved into a heatsetting chamber where it is heatset, the improved method of removing water from the tow by guiding the tow immediately from the heated water bath to and displacing it under and around the surface of an improved dewatering jet device and partly wrapping the tow around that portion of the dewatering jet device within which is the jet opening through which air is blown against the wrapped around portion toward the upstream portion of the tow and through the tow. The improved dewatering jet device is a cylindrical body member provided with an axially extending slotlike opening having substantially parallel walls and a depth to width ratio of about 5:1 and a radius on the outer lips of the opening of about 1/32 inch.

[ Oct. 7, 1975 TOW DEWATERING JET DEVICE [75] Inventors: Donald L.Finley; Edward A.

Morehead, both of Kingsport, Tenn.

[73] Assignee: Eastman Kodak Company,

Rochester, NY.

[22] Filed: Dec. 13, 1973 21 Appl. No.: 424,518

Related US. Application Data [62] Division of Ser, No, 257,406, May 26,1972, Pat. No.

[52] US. Cl. 239/597; 239/601; 28/713; 34/23; 34/155; 68/20 [51] Int.Cl. F26B 5/14; B05B 1/04; B05B 1/20;

[58] Field of Search... 239/289, 568, 589, 597-599, 239/601,16O2; 15/306A; 19/66 T; 28/713,

3,257,734 6/1966 Boadway et al. 34/23 X 3,286,307 11/1966 Watson 19/66 T3,574,261 4/1971 Bailey 1 34/23 3,606,974 9/1971 Steele 239/597 XPrimary ExaminerRobert S. Ward, Jr.

[57] ABSTRACT In a process for treating continuous length filamentarytow of man-made fiber that is moved through a heated water bath, draftedand then in due course of processing is subsequently moved into aheatsetting chamber where it is heatset, the improved method of removingwater from the tow by guiding the tow immediately from the heated waterbath to and displacing it under and around the surface of an improveddewatering jet device and partly wrapping the tow around that portion ofthe dewatering jet device within which is the jet opening through whichair is blown against the wrapped around portion toward the upstreamportion of the tow and through the tow. The improved dewatering jetdevice is a cylindrical body member provided with an axially extendingslot-like opening having substantially parallel walls and a depth towidth ratio of about 5:1 and a radius on the outer lips of the openingof about 1/32 inch 2 Claims, 10 Drawing Figures Sheet 1 0f 5 Oct. 7,1975

U.S. Patent U.S.' Patent Oct. 7,1975 Sheet 2 of 5 3,910,320

U.S. Patent Oct. 7,1975 Sheet 3 of5 3,910,320

m 6z .8 6 E 93 k 323 it; as 255mm miwzoiimm mmwmom 2: 3oz, $5: ow mm mm@m mm 3 mm mm 3 NM ow Q 2 1 N 9 m w v E mozoummmrou US. Patent Oct.7,1975 Sheet 4 of5 3,910,320

#6 (3 EFFECT OF TOW DISPLACEMENT ON JET DEVICE WATER REMOVAL IN TERMS OFTEMPERATURE ZIO TEMPERATURE (C) 63 55 01 O 1/ I0 II/8 I Tow DISPLACEMENT(INCHES) AIR PRESSURE AIR FLOW (GEM) a 8 AIR PRESSURE (RSIG) AIR FLOW I0I l Tow DISPLACEMENT (INCHES) 37g 9 EFFECT OF TOW DISPLACEMENT BY JETDEVICE ON AIR FLOW RATES AND AIR PRESSURE TOW DEWATERING JET DEVICE Thisis a division of application Ser. No. 257,406 filed May 26, 1972 now US.Pat/No. 3,786,574.

BACKGROUND OF THE INVENTION This invention is directed to a method andto apparatus for practicing the method by which liquids are removed froma continuous length tow of filamentary material such as a tow ofsynthetic or manmade polymeric material while the material is undergoingvarious processing operations in the production of textile fibers.

In the production of textile fibers from continuous length syntheticfiber tow, the tow is transported through various treating stations,such as heating, drafting, heatsetting, cooling, crimping, or crimpingand then heatsetting followed by cooling, and other operations,depending upon the desired physical and chemical properties to beimparted to the fibers in the tow. One well-known practice is that ofheatsetting synthetic or man-made materials, such as materials includingpolyester fibers of polyethylene terephthalate, at a constant length inorder to produce a high tenacity fiber. The Hebeler patent, US. Pat. No.3,044,250 granted July 17, 1962, and the Patton et al. patent, US. Pat.No. 3,500,553 granted March 17, 1970, discuss holding continuous lengthfilaments of tow at constant length while the tow is being heatset.Regular tenacity fibers of polyester, for instance, as distinguishedfrom high tenacity polyester fibers, are usually heatset under freeshrink conditions. In either instance, however, the fibers have usuallyundergone treatment in a liquid bath at some stage prior to heatsettingand cannot be brought up to heatsetting temperatures until the liquidhas been substantially removed or evaporated in some manner. Inreference again to synthetic fiber such as polyethylene terephthalate,the desired temperature for heatsetting is usually such that cannot bereadily obtained unless the moisture or liquid from the water bath hasbeen removed and the fiber becomes bone-dry so that the fiber can bebrought up to temperature of about 200C. and held at that temperaturefor a predetermined length of time.

It is critical that the fiber tow be heated uniformly; if moisture orliquid remains on part of the fibers making up the tow while the dryfibers in the tow are brought up to the desired heatsetting temperature,the later processed staple fibers will not be a desirable qualityproduct that has useful sale value. The difficulty in removing suchliquid stems from the fact that the liquid, such as water, is trappedbetween the filaments of the tow, and there may be hundreds of thousandsof filaments in a tow, For instance, a tow band having a width of about8 inches and a thickness of about 3/32 inch may have in excess of600,000 continuous length filaments, The size of the tow band and thenumber of filaments will differ, of course, depending upon a number offactors. Water will not only be trapped between the filaments but alsothe filaments on the outer surfaces of the tow or tow band tend to serveas insulation for the filaments inwardly of the surface filaments,thereby making it difficult to evaporate the trapped liquid and raisethe temperature of the filaments that are encased the roll being usedsingly or in series to heat tow passing partly therearound to reduce themoisture content in the tow to a predetermined extent prior to theoperation of heatsetting. Although this approach is effective inapplying heat uniformly to the tow, the fabrication of the rolls iscomplex and expensive.

Another method disclosed for removing liquid that appears to be lesscomplex and less expensive in fabrication is shown in the Osban et al.patent, US. Pat. No. 3,199,214 granted Aug. 10, 1965. The patentdiscloses passing under tension a wet synthetic fiber tow band under onehollow conduit and over a following hollow conduit, with each hollowconduit being provided with orifices through which gas moving at a highvelocity is directed against the tow band as it passes across and isdeflected by each of the hollow conduits. According to the patent, thehigh velocity gas removes excess liquid from the tow band and slightlyopens up the tow to provide passageways communicating between eachfilament of the tow and the surrounding environment in preparationfor'subsequent treatment. It is necessary to open up the tow somewhat inpreparation for a subsequent treatment because the squeeze rolls priorto the two hollow conduits served to compress the tow and compact thefilaments of the tow into a relatively dense impermeable mass". Thesubsequent treatment illustrated is a conditioner wherein the tow may betreated by surrounding it with heated unsaturated humid air forconditioning the filaments by evaporation of moisture therefrom.

SUMMARY OF THE INVENTION In a process for treating continuous lengthfilamentary tow of man-made fiber that is moved through a heated waterbath, drafted and then in due course of processing is subsequently movedinto a heatsetting chamber where it is heatset, the invention,therefore, provides an improved apparatus for practicing the improvedmethod by which the tow is displaced or deflected from its path and isguided under a dewatering jet device that is positioned at thedownstream exit from and above the heated water bath. The tow isdeflected around that portion of the surface of the dewatering jetdevice within which is the opening through which air is blown, thedeflection being predominantly on the downstream side of the dewateringjet device with respect to the movement of the tow, and water is removedby blowing air from the opening of the dewatering jet device against thesurface of and through the tow so that most of the water is primarilyblown upstream of the tow while other water is blown through the tow inreturn to the water bath. The improved dewatering jet device is acylindrical hollow body member of predetermined length and is providedwith a slot-like opening extending over a portion of the length of thebody member and having substantially parallel walls and a depth to widthratio of about 5:1 and a radius on the outer lips of the opening ofabout 1/32 inch.

For reasons unknown to the inventors, it has been found that bypositioning a dewatering jet device, which has a slot-like opening orslot having the depth to width ratio of 5:1, at the exit of the heatedwater bath where the tow has just emerged from the water, not only is agreater amount of water removed subsequently enabling the tow to be moreeffectively and uniformly heatset but also the jet device is not noisyand deafening to operating personnel and it is more economical to usebecause it requires less air consumption. It was found that the resultswere significantly different over those resulting from positioning thedewatering jet device farther downstream of the processing line wherethere was less water remaining on the tow. In the latter instance thedewatering jet device used more air, removed proportionately less waterfrom the tow and was deafening to operating personnel with a decibelrating of about 103 dBA, as measured on the A scale of a standard soundlevel meter. On the other hand, the dewatering jet device at the exit ofthe heated water bath could not be detected against a background noiseof about 90 to 92 dBA. Under the Occupational Noise Exposure section,US. Department of Labor Safety and Health Standards, Table I, (FederalRegister, Volume 34, No. 96, May 20, 1969, including corrections issuedin July, 1969, Walsh-Healey Regulation) the permissible noise exposureduration at 103 dBA for operating personnel is slightly over 1 hour butless than 1% hours per day. The permissible noise exposure for 90 to 92dBA is from 8 to 6 hours per day, respectively.

The inventors have also found that a correlation can be establishedbetween temperature readings, taken for instance at the exit end of theheatsetting oven (not shown) and effective location, adjustment andangular orientation of the dewatering jet device. This assumes, ofcourse, that other conditions on the tow processing line remain thesame.

In using such temperatures correlation inventors have discovered thatfor removing water and most effective position for the dewatering jetdevice is at the exit of the heated water bath; with the slot throughwhich air is emitted being angularly oriented so that its axis or jetslot angle B, as measured from the upstream tangent point at thebeginning of the wrapping engagement made by the tow with the jet devicetoward the downstream tangent point where the tow terminates contactwith the jet device, extends from about 3 to about 8; with the wrapangle A extending correspondingly in the range of about 12 to about 40.It has also been discovered that when the dewatering jet device ispressed against the tow to deflect or displace the tow about one-halfinch from its straight line path as its emerges from the heated waterbath toward the first roll in a drafter roll section the most amount ofwater is removed. It has further been discovered, however, that bypressing the dewatering jet device still further against the tow untilthe extent of deflection or displacement of the tow is about 1% inches,the least amount of air flow is used to achieve about the same amount ofwater removal as occured at one-half inch displacement.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is an elevational view of a portion of a tow processing lineshowing a first drafter roll section, a heated water bath, thedewatering jet device at the exit of the tow from the heated water bath,followed by a second drafter roll section;

FIG. 2 is an enlarged elevational view of a portion of FIG. 1 in whichmay be seen water being removed in a fog or spray by the dewatering jetdevice;

FIG. 3 is an enlarged elevational view of a portion of FIG. 1 butillustrating an alternate arrangement wherein snubber bars are employedbefore and after the dewatering jet device;

FIG. 4 is a view of the dewatering jet device;

FIG. 5 is a cross-sectional view of the dewatering jet device takenalong line 55 of FIG. 4;

FIGS. 6 and 7 show, respectively, a graphic illustration of the jet slotangle relative to the tow wrap angle, and a graph illustrating therelationship of the two angles as to water removal efficiency;

FIG. 8 is a graph illustrating effect of tow displacement or deflectionby dewatering jet device on water removal efficiency;

FIG. 9 is a graph illustrating effect of tow displacement or deflectionby dewatering jet device on air flow rates and air pressure; and

FIG. 10 is a graph illustrating effect on tow temperature without adewatering jet device, by a dewatering jet device located at the waterbath, by a jet device located at the second drafter roll section, and byjet devices in tandem operation at both the water bath and the seconddrafter roll section.

DESCRIPTION OF THE PREFERRED EMBODIMENT In reference to the drawings,and initially to FIG. 1, the tow 10, a continuous length filamentary towof man-made fiber, such as polyester tow, enters a first drafter rollsection 12 with the rolls 14 being driven at a predetermined rate ofspeed. The tow then enters a heated water bath indicated at 16 where thetow is heated to a predetermined temperature preparatory to beingdrafted by the second drafter roll section 18. The rolls 20 of thesecond drafter roll section are driven at a predetermined rate of speedgreater than the rate of speed of the rolls of the first drafter rollsection in order to draft the tow to a predetermined extent. The towemerges from the heated water bath and passes under and into engagementwith dewatering jet device 22 that is positioned at the exit of andabove the heated water bath. The tow is displaced or deflected partlyaround and by the jet device from the path the tow would otherwisefollow between the heated water bath and the first roll engaged by thetow on the second drafter roll section 18. Water is removed from the towby the dewatering jet device to a predetermined extent preparatory tosubsequent processing of the tow following the second drafter rollsection. Such subsequent processing includes heat treating of the tow(not shown) in a manner well known in the art, such as illustrated inthe aforementioned patents to Hebeler and Patton et al.

The extent to which the dewatering jet device may be depressed againstthe tow may be dependent upon the spacing between the tow and thestructure supporting the bath, and the location of the tow guide member24 in the heated water bath relative to the location of the first rollin the second drafter roll section to be contacted by the tow. It may bedesirable, especially if the tow is spaced relatively close to theheated water bath with insufficient space to obtain desired wrap angle,to aid the displacement of the tow by means of snubber bars 26 and 28shown in an alternate arrangement (FIG. 3) in which the wrap angle A maybe increased by depressing against the tow the dewatering jet device 22'between the snubber bars to a predetermined distance. Anadditionaladvantage derived from use of snubber bars to either side ofthe dewatering jet device is that some squeegee action occurs with waterbeing removed from the underside surface of the tow. In the alternatearrangement of Fig. 3 components that are the same as that disclosed inFIGS. 1 and 2 have been identified by the same reference numbers whichhave prime marks beside them to distinguish the alternate arrangementfrom the arrangement disclosed in FIGS. 1 and 2.

FIGS. 4 and 5 disclose in more detail the construction of the dewateringjet device '22 (FIGS. 1 and 2) or 22' (FIG. 3) which comprises acylindrical body member 30 of a predetermined length and defining alongits length an axially extending slot 32 of a length dependent upon thewidth of the tow to be treated. For reasons not entirely clear toinventors it has been found that effective water removal occurs when thedepth of the slot in the cylindrical body member is about five times thewidth of the slot and with substantially paral lel walls. This canreadily be achieved by selectingcy lindrical hollow bar stock meetingthe following conditions:

wherein R the inner radius of the body member; R the outer radius of thebody member; and W the width of the slot, as may be observed from FIG.5. Another factor that appears to have some significance is theformation of a small radius 34 at each of the outer lips of the slot 32.If the radius is too small the lips will be too sharp and the tow willbe damaged. In the in stance of the particular body member 30illustrated, with the outside diameter of the body member being about1.312 inches, the small lip radius of the slot lips is about 1/32 inchor 0.031 inch, the slot width is about 1/16 inch or 0.062 inch and thedepth of the slot is about 5/16 inch or 0.312 inch. It is thought thatthe air flow is straightened out more with this deep parallel wall slotconstruction and that the particularly small lip radius decreases Coandaeffect around the lips for better air penetration of the tow and thusremoves more water. In the operation of the dewatering jet device, thedevice may be suitably adjusted both in an angular orientation of theslot relative to the tow and depression against the tow by mechanicalstructure (not shown) that will support the device for such adjustments.The material from which the body member 30 is made is preferably anon-plucking, wear resistant material. For instance, the deviceillustrated is made of stainless steel and detonation coated such as byUnion Carbide with their UCAR LA-2 (pure aluminum oxide) and lapped to arms (root means square) microinch finish.

The purpose of the jet device is to remove the water that is heldbetween the filaments in the tow band, and when this is done, and ifdone effectively, the tow will then present a smaller heat load to theheatset oven. The air emitted from the slot against the displaced tow isin effect compressed and in passing through the tow strips off the waterheld between the filaments. Some of the air will blow along the top ofthe tow stripping the water from the surface of the tow, while some airwill pass entirely through the tow, but most of the air seems topenetrate into the tow and travel for a short distance between thefilaments before emerging in the form of a spray or fog directed back tothe heated water bath, depending upon adjustment, the spray or fog beingillustrated in the drawings. It is also thought that there may be somesealing effect of the slot dependent upon the extent of wrap angle andjet slot anglethat the tow makes with respect to the dewatering jetdevice so that the air is compressed as it is emitted fromthe slot andthus is forced into and between the filaments making up the tow band ortow. It has been observed that the slot is substantially sealed off whenthe slot is about the center of the wrap angle so that little air isemitted.

As stated previously, with the discovery of being able to rely upon towtemperatures, such as might be taken at the exit of the heatset oven(not shown), it is possible to determine an effective location for thedewatering jet device, effective slot angular orientation, and effectivetow displacement by depression of the dewatering jet device into thetow.

FIGS. 6 and 7 illustrate the relationship between tow wrap angle and jetslot angle with wrap angle being measured from the upstream tangentpoint 36, which is at the beginning of tow contact with the dewateringjet device, toward the downstream tangent point 38, which is where thetow moves out of contact with the jet device on its way to the seconddrafter roll section 18. The wrap angle is designated A; and the jetslot angle is designated B, which is measured from the up stream tangentpoint 36 toward the downstream tangent point 38 to the center or axis ofthe slot. In order to understand the significance of the graph shown inFIG. 7 it is necessary to correlate this with the other illustratedgraphs that will be described herein.

The graph in FIG. 8 illustrates the effect of tow displacement on waterremoval in terms of temperature, and it may be observed that when thetow is displaced by the jet device about one-half inch, the maximumtemperature results, with further tow displacements up to and including1 /4) inches resulting in approximately the same temperature as thatwith one half inch displacement.

The graph in FIG. 9, however, illustrates the effect of tow displacementby the jet device on air flow rates and air pressure and shows that byincreasing the displacement of the tow from /2 inch up to about (1%,)inches a more economical air flow in cubic feet per minute is achieved.It will thus be seen that increasing the tow displacement results inincreased air pressure and decreased air flow.

In reference again to FIG. 7 when the tow is displaced one-half inch thewrap angle A is about and the slot angle B is about 3; and when the towdisplacement is about 1% inches the wrap angle A is about 40 and theslot anglee B is about 8.

FIG. 10 shows the effect on heatset tow temperature by comparing adewatering jet device located at the heated water bath with a dewateringjet device located at the second drafter roll section, and in tandemoperation with jet devices being located at the water bath and at 40 inthe second drafter roll section, as shown in phantom lines in FIG. 1. Itwill readily be observed that when jet devices are operated in tandem,i.e., at two 10- cations at the same time, the water removal as shown bytemperature increase is only slightly improved over the use of adewatering jet device located at only the heated water bath; and thatthe use of the dewatering jet device at the heated water bath shows asignificant improvement in terms of temperature over a situation wherethere is no dewatering jet device in operation. The graph further showsthat when the measurements were repeated successively, as viewed fromleft to right, the two sets of results were fairly repeatable.

It has been found, therefore, that the particular location, adjustmentand angular orientation, and the jet slot depth to width ratio of thedewatering jet device have produced unexpected results in terms of waterremoval efficiency, relative quiet operation and lower air consumption.The hollow conduit devices shown in the aforementioned Osban et al US.Pat. No. 3,l99,2l4, for instance, do not appear to recognize thecriticalness of jet orifice size, angular orientation, and spacing ofthe hollow conduit devices from the water bath. Inventors cannot explainwhy the above described factors are proving to be effective; but canonly offer some theories as speculated upon above. Dewatering jetdevices placed at other locations along the tow processing line have notbeen found to be as significantly effective as the location describedherein at the heated water bath. Similarly, the mere punching of holesor slots in hollow rods or conduits without giving any regard to size,shape and the like of such holes or slots has not appeared to be assignificant as that described herein. The nature of this operation issuch that can only be evaluated on an actual production line. It is forthis reason that the actual noise made by the dewatering jet device atthe water bath could not be detected over that of the operating towlines. It is only known that by placing the dewateringjet devicedownstream at the second drafter roll section or at other locationsresulted in a noise factor that could not be tolerated for any length oftime by operating personnel, the noise was significantly noticeable; butat the water bath location whatever noise was made could not be pickedup by the sound meter against the ambient background noise.

While the invention has been described in detail with particularreference to preferred embodiments thereof, it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention as described hereinabove and as defined in the appendedclaims.

We claim:

I. An improved dewatering jet comprising a cylindrical hollow member ofpredetermined length and defining through the wall of the member aslot-like opening extending over a portion of the length of the memberand having substantially parallel walls and a depth to width ratio ofabout 5:1 and a radius on the outer lips of the opening of about 1/32inch.

2. An improved dewatering jet as defined in claim 1, and wherein thewidth of the slot-like opening is about 1/16 inch and the depth thereofis about 5/16 inch.

1. An improved dewatering jet comprising a cylindrical hollow member ofpredetermined length and defining through the wall of the member aslot-like opening extending over a portion of the length of the memberand having substantially parallel walls and a depth to width ratio ofabout 5:1 and a radius on the outer lips of the opening of about 1/32inch.
 2. An improved dewatering jet as defined in claim 1, and whereinthe width of the slot-like opening is about 1/16 inch and the depththereof is about 5/16 inch.